Centrifuge tube assembly for separating, concentrating and aspirating constituents of a fluid product

ABSTRACT

A centrifuge tube assembly includes an elongate tubular receptacle having upper and lower ends and a side wall that extends between the ends. A cap attached to the receptacle carries a common inlet/outlet port formed therethrough for communication with an interior chamber of the tubular receptacle. A liquid impermeable piston is longitudinally movable through the receptacle chamber and sealably interengages an interior wall of the receptacle. The piston separates upper and lower regions of the chamber, which respectively communicate with the inlet/outlet port and a pressure neutralizing vent. Biological products are introduced into and aspirated from the receptacle through the inlet/outlet port.

RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/741,920 filed Jun. 17, 2015.

FIELD OF THE INVENTION

This invention relates to a centrifuge tube, that enables fluidbiological products such as blood, stem cells, bone marrow aspirate andthe like to be effectively separated and concentrated into constituentcomponents, which may be conveniently aspirated after the biologicalproduct has been centrifuged. The apparatus is particularly effectivefor sequestering platelet-rich plasma and bone marrow aspirate for usein surgical, medical and veterinary procedures.

BACKGROUND OF THE INVENTION

Platelet-rich blood plasma is required for use in various medicalprocedures. This blood product is particularly effective due to itsgrowth promoting features, which assist greatly in wound healing andbone regeneration. Presently, blood plasma with a high concentration ofplatelets is utilized for dental implants and other periodontalprocedures, facial reconstruction, oral or maxillofacial surgery andchronic wound care. In order to obtain a required concentration ofplatelets, a blood sample normally must be centrifuged in order toseparate the blood into its component blood products (i.e. plasma, redblood cells and platelets). The platelets, typically in a form of awhite “buffy coat”, are then separated from the blood sample andsequestered in concentrated form through aspiration. Conventionalaspiration techniques often fail to provide a satisfactory concentrationof platelets. Cross-contamination between the constituent products isfrequently encountered. We have determined that the need exists for acost effective apparatus that facilitates the sequestration of plateletswhile minimizing cross-contamination between blood components.

The centrifuge tube assemblies disclosed in U.S. Pat. Nos. 6,835,353 and7,976,796 were developed to address the foregoing concerns. Thosedevices employ various arrangements of aspiration pipes, which areincorporated into the centrifuge tube. Although these products achievesuperior results and have proven to constitute a significant improvementover the prior art, I have determined that the need exists for an evensimpler, more efficient and more reliable design.

An improved centrifuge tube is needed for separating and aspirating ahost of biological products, including but not limited to bloodproducts, bodily fluids, stem cells, bone marrow aspirate, etc. for usein both medical and veterinary applications. It is important for suchproducts to be separated and concentrated into constituent componentsquickly, effectively and without causing cross-contamination of thosecomponents.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a simpler,more efficient and yet highly reliable centrifuge tube that enablesblood, bone marrow aspirate and other fluid biological products to beeffectively separated and concentrated into constituent components andconveniently aspirated following separation.

It is a further object of this invention to provide a centrifuge tubewith aspirating capabilities that is manufactured much less intricatelyand far less expensively than existing devices of this type.

It is a further object of this invention to provide an aspiratingcentrifuge tube that is extremely simple to operate.

It is a further object of this invention to provide a centrifuge tubethat permits a host of chemicals, bodily fluids and other biologicalproducts to be separated and individually aspirated with minimalcross-contamination.

It is a further object of this invention to provide a centrifuge tubeassembly that minimizes potential contamination of biological liquidswhile such liquids are injected into and aspirated from the tube.

It is a further object of this invention to provide a centrifuge tubedevice that features an improved, secure cover that maintains sterilityof the centrifuged fluids, prevents aereosolization and eliminates theneed to use centrifugal bucket caps.

It is a further object of this invention to provide a centrifuge tubeassembly that eliminates the use of aspirating tubes entirety so thatmanufacturing complexity and costs are reduced and more volume is madeavailable in the tube for accommodating fluids.

It is a further object of this invention to provide a centrifuge tubeassembly that facilitates aspiration by eliminating aspiration pipes,which are subject to kinking and malfunction.

It is a further object of this invention to provide a centrifuge tubethat is particularly effective for sequestering a high concentration ofplatelet-rich plasma for use in various medical, surgical and veterinaryprocedures.

It is a further object of this invention to provide an aspiratingcentrifuge tube that may be used effectively for separating andaspirating a wide range of biological products, including but limited toblood, stem cells, bone marrow aspirate, etc.

It is a further object of this invention to provide a centrifuge tubethat may be used effectively in various medical and veterinaryapplications.

This invention features a centrifuge tube assembly preferably in theform of an elongate tubular receptacle. The receptacle may include anopposite upper and lower ends and a side wall that extends between theupper and lower end walls. A cap engages the side wall and extendsacross the upper end of the receptacle. A common inlet and outlet portis formed through the cap in communication with an interior chamber ofthe tubular receptacle. A liquid impermeable diaphragm or piston ismounted within the chamber of the tubular receptacle for sealableengaging the interior surface of the side wall of the receptacle andsliding longitudinally through the receptacle. Blood product or otherbiological fluid is introduced through the inlet/outlet port into aregion of the chamber between the piston and the upper end of thereceptacle. The piston is driven downwardly through the tubularreceptacle as the fluid is introduced. The tube device is centrifuged toseparate the fluid into constituent components. One or more layers ofthe separated fluid may then be conveniently aspirated through thecommon inlet/outlet port. A vent is formed through the lower end of thereceptacle for equalizing or neutralizing air pressure in the receptaclechamber when either fluid is introduced into the chamber or constituentcomponents are aspirated from the chamber.

In a preferred embodiment, the cap is removably connected to the sidewall of the tubular receptacle. The opposite, lower end of the tubularreceptacle may include an annular base for supporting the tubularreceptacle to extend upwardly from an underlying surface.

The piston may be slidable longitudinally within the tubular receptaclewhile maintaining peripheral sealing engagement with the interior wallof the tubular receptacle. The piston may carry an annular O-ring thatsealably interengages the interior surface of the side wall.

The cap may include a tapered or conical channel that communicates withthe common inlet and outlet port for facilitating aspiration of the oneor more fluid layers therethrough. The vent may carry a filter forrestricting the entry of contaminants into the chamber through the vent.

A method of separating fluid biological product into constituentcomponents using the foregoing assembly is also featured. Initially, ablood sample or other fluid biological product is introduced into thetubular receptacle formed through the common inlet/outlet port. Asbiological product is introduced into the tubular receptacle, it pushesthe sealing piston downwardly within the tubular receptacle against theneutral air pressure of a vented region of the receptacle chamber formedbetween the piston and the lower end wall of the receptacle. When thereceptacle is filled with a fluid biological product to a desired level,the inlet/outlet port is closed and the assembly is centrifuged toseparate the fluid product into constituent components. The inlet/outletport is then opened and one or more of the constituent components areaspirated through the inlet/outlet port. Once again, the vent providesfor neutral pressurization within the receptacle so that aspiration isfacilitated. As successive layers of constituent components are removedfrom the centrifuge tube, air is pulled into the receptacle through thevent and the piston is drawn upwardly through the tubular receptacle.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages will occur from the followingdescription of a preferred embodiment and the accompanying drawings, inwhich:

FIG. 1 is an elevational cross sectional view of a preferred embodimentof the centrifuge tube assembly of this invention without any fluid orother biological product within the tubular receptacle:

FIG. 1A is a cross sectional view taken along line 1A-1A of FIG. 1;

FIG. 2 is an exploded view of the assembly depicting the individualcomponents of the preferred device;

FIG. 3 is a perspective view of a vent element and filter used in theassembly;

FIG. 3A is a cross sectional view of the vent plug and filter;

FIG. 4 is a view similar to FIG. 1 with the cover and port closureremoved and a hypodermic syringe positioned for operably engaging thereceptacle; a biological fluid to be separated is depicted in thetubular receptacle;

FIG. 5 is a view similar to FIG. 1 wherein the tube has been centrifugedto separate a blood product in the tube into two constituent components;namely red blood cells and plasma, with the plasma layer positioned sothat it can be aspirated from the tube first;

FIG. 6 is a view similar to FIG. 4 wherein a hypodermic syringe engagedwith the tube is being operated to aspirate successive constituentcomponents of the biological product from the tube; and

FIG. 7 is a view similar to FIG. 5 with the tube inverted so that thecentrifuged blood product is oriented in layers that permit red bloodcells to be aspirated from the tube first.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

There is shown in FIG. 1 a centrifuge tube assembly 10 that includes atubular or cylindrical receptacle 12 having an open upper end and anopposite lower end 14. A cylindrical side wall 16 extends between lowerend 14 and upper end 13. Tubular receptacle 12 further includes aninterior chamber 18 that extends from lower end 14 to upper end 13. Thischamber accommodates blood, chemicals, stem cells, bone marrow aspirateor other biological fluids/products to be centrifuged and aspiratedusing assembly 10.

As used herein, “centrifuge tube” should be understood to comprisevarious shapes and sizes of vessels, receptacles and containers havingan interior chamber for holding a fluid biological product and capableof being centrifuged to separate the product into constituentcomponents. The centrifuge tube is not limited to just tubular andelongate configurations, although such configurations will typically beused in preferred embodiments of the invention.

As best shown in FIG. 2, an annular notch 20 is formed at the upper end13 of side wall 16. This notch enables an upper end cap 36 to securelyand sealably interengage receptacle 12 as will be further describedbelow. Lower end 14 of receptacle 12 includes a floor 22 that definesthe bottom of interior chamber 18. An annular base 15 is connectedunitarily with and depends from receptacle floor 22 and side wall 16.The annular base stably supports the tubular receptacle in an uprightcondition on a table or other flat or horizontal surface. In this way,the centrifuge tube assembly does not require a separate rack or holderfor support. Annular base 15 also securely supports the device 10upright in a standard centrifuge machine in accordance with theorientation depicted in FIGS. 1 and 5.

Tubular receptacle 12 is typically composed of a durable plasticmaterial such as polypropylene or other material suitable for medical orveterinary applications. The tube should also be constructed towithstand the forces exerted by centrifuging. In certain applications,shatter resistant glass may be employed.

A plurality of graduated volume markings, not shown herein but see U.S.Pat. No. 7,976,796, may be formed at various selected intervals alongthe exterior side wall of tubular receptacle 12. Such markings should beformed at heights or intervals corresponding to commonly selectedvolumes of biological product that will be introduced into the tube.Such markings may be varied within the scope of this invention.

A vent hole 24, FIG. 2, is formed through floor 22 and communicablyinterconnects chamber 18 and a space 26 surrounded by annular base 15.Vent hole 24 receives a vent plug 28 to define a pressure equalizing orneutralizing vent in receptacle 12. As shown in FIG. 3, vent plug 28includes a central channel 30 that extends fully through the vent plug.The channel accommodates an air filter 32. Vent plug 28 defines an airpressure equalizing vent that functions in the use of centrifuge tubeassembly as described below. Alternative vent constructions formedunitarily with or separably from receptacle 12 may be utilized withinthe scope of this invention.

As shown in FIGS. 1 and 2, cap 36 is releasably engaged with open upperend 13 of receptacle 12. Cap 36 includes a generally cylindrical shapethat conforms the cross sectional shape of the receptacle shown in HG.1A. The cap features an upper lid 38. FIGS. 1 and 2, having a circularshape that generally matches the circular cross sectional shape of thereceptacle. An annular or cylindrical flange 40 is attached unitarily toand depends from lid 38. A conically tapered channel 42 is formed in theunderside of flange 40. The flange is configured and sized such that itcan be slid snugly and securely into interior chamber 18 of receptacle12, as shown in FIG. 1. This effectively closes the receptacle so thatit may be used in the manner disclosed herein. Lid 38 includes aperipheral lip 45, shown in FIG. 1, that interengages the peripheralnotch 20 formed at upper end 13 of receptacle 12 when cap 38 is insertedinto chamber 18. In this state, cap 36 is securely and snugly engagedwith the receptacle. The interconnection is tight enough so that the capremains in secure interengagement with the upper end of the receptacleduring centrifuging of assembly 10 and subsequent fluid aspirationtherefrom.

Conically tapered interior channel 42 of cap 36 is communicablyconnected with a single common inlet/outlet port 44 formed eitherunitarily or separately through lid 38 of cap 36. Port 44 includes acentral opening that extends through lid 38. The upper end or stem 35,of port 44 is disposed exteriorly of a tubular receptacle, whereas thelower end of the inlet/outlet port communicates with the conicallytapered channel 42. As a result, when cap 36 is interengaged with theopen upper end 13 of receptacle 12, port 44 provides for exteriorcommunication with the interior chamber 18 of receptacle 12.

A removable plastic closure 48 is preferably secured to the outer stemof port 44 by a connecting strap, not shown herein but see U.S. Pat. No.7,976,796. During the centrifuging operation, as well as at other timeswhen fluid is not being introduced into or removed from the tube,closure 48 is engaged with the upper exterior end of port 44 to maintainthe port in a closed condition. The risks of fluid spillage andcontamination are thereby reduced.

Although the receptacle is preferably formed with an open upper endinterengaged by removable cap 36, in alternative embodiments, apermanently capped upper end may be utilized. Various alternative and/oranalogous forms of construction for the upper end cap and commoninlet/outlet port are disclosed in U.S. Pat. Nos. 6,835,353 and7,976,796 the disclosures of which are incorporated herein by reference.Preferably cap 36 as well as inlet/outlet port 44 are likewise composedof polypropylene or other material similar to that forming the tubularreceptacle itself. Normally, the common inlet/outlet port is moldedtogether with the cap in a single manufacturing process. Associatedtypes of integral and separated inlet/outlet ports may be utilizedincluding Luer™ type ports as are described in U.S. Pat. No. 6,835,353and 7,976,796.

As further shown in FIGS. 1 and 2, the exterior stem 35 of port 44extends centrally from a threaded connection 46 that is formed unitarilyon the upper surface of lid 38. Threads 46 are operably interengageableby complementary threads 52 formed interiorly on a removable tube cover50. The removable cover has a generally circular cross sectional shapethat corresponds to that of the centrifuge tube. In particular, cover 50includes a cylindrical peripheral wall 54 and a flat top surface 56.When cap 36 is interengaged with receptacle 12 and cover 50 isthreadably attached to cap 36, the flat top surface 56 allows thecentrifuge tube assembly 10 to stand stably in an upright, invertedcondition upon an underlying table or other flat surface. The flat topsurface 56 also allows the assembly to be supported upright securely inan inverted condition within a standard centrifuge machine while thecentrifuging operation is being performed. This is described more fullybelow. Cap 50 is preferably composed of a plastic or glass materialsimilar to that comprising the other components of the assembly.

As previously described, a vent plug 28 is formed centrally throughfloor 22 of receptacle 12. This vent maintains a stable neutral pressurewithin tubular receptacle 12 during fluid injection and aspiration. Itis critical that the vent be formed in the end of the tube opposite thecapped end wherein the common inlet/outlet port is formed or otherwisein communication with a region of chamber 18 that does not communicatewith port 44. This allows constituent separation and aspiration to beperformed quickly and efficiently without the need for one or moreaspiration pipes.

A liquid impermeable piston 60 is contained in chamber 18 and slidablymounted for longitudinal movement within chamber 18 of tubularreceptacle 12. More particularly, as also shown in FIG. 1A, piston 60has a generally circular, peripheral shape conforming to the interiorshape of side wall 16. The piston features an annular peripheral groove62. The groove accommodates an O-ring 64, which sealingly and slidablyinterengages the interior surface of side wall 16 of tubular receptacle12. Piston 60 is movable longitudinally within chamber 18 of tubularreceptacle 12 as indicated by doubleheaded arrow 63 FIG. 1. The uppersurface 66 of piston 60 has a concave shape. The bottom surface 67 ofpiston 60 includes a central recess 69 that receives the upper interiorend of vent plug 28 when piston 60 is pushed to its lowest positionwithin chamber 18 during operation of assembly 10, as described below.

Prior to usage of assembly 10, sealing piston 60 is typically positionedwithin chamber 18 of receptacle 12 proximate the upper end 13 of thereceptacle Cap 36 is engaged with receptacle 12 as previously describedand closure 48 is engaged with inlet/outlet port 44 so that the interiorchamber 18 of receptacle 12 is closed. Cover 50 may also be attached tothe cap in order to further isolate and enclose chamber 18 and to reducethe risk of fluid contamination during use of assembly 10.

Assembly 10 is utilized to centrifuge a biological product into itsconstituent components and then to aspirate one or more of thosecomponents as shown in FIGS. 4-6. A preferred representative use forcentrifuge tube assembly 10 is the separation of a blood sample intoconstituent blood components. Typically, it is desirable to separateplatelets and/or plasma from red blood cells such that a platelet-richblood product may be used in various surgical, medical or veterinaryapplications. This process is performed in the following manner usingassembly 10, Initially, the empty receptacle 12 is stood upright on anunderlying table T with on its base 15 supporting the assembly upon thetable as shown in FIG. 1. Cover 50 is disengaged from cap 36 and closure48 is removed from port 44. Blood product F (or an alternative fluidbiological product) is then added to receptacle 12 as depicted in FIG.4. Specifically, a hypodermic syringe H carrying the blood or otherbiological product is operably engaged with upper stem 35 ofinlet/outlet port 44. The tip T of hypodermic syringe H may be engagedwith port 44 in a conventional manner. See U.S. Pat. Nos. 6,835,353 and7,976,796. Exterior stern 35 holds dispensing tip T securely in place sothat the hypodermic syringe is securely engaged with assembly 10. Thesyringe is then operated in a conventional manner to inject andintroduce the product to be separated through port 44 and into theinterior chamber 18 of receptacle 12. More particularly, blood productor other biological product F (e.g. bone marrow) is transmitted throughport 44 into a first, upper space or region 86 of chamber 18 located onone side of the piston between cap 36 and piston 60. As biologicalproduct F is introduced into space 86, the increasing volume andpressure of fluid product F in region 86 drives piston 60 downwardly, asindicated by arrows 70. Blood product is injected into the receptacle bysyringe H in this manner until the desired volume of fluid is added tochamber 18. Vent plug 28 allows air within a second region 89 of thechamber on the opposite side of piston 60 (between the descending pistonand the lower end 14 of receptacle 12) to escape from the chamberthrough the vent plug so that the air pressure in the receptacle isneutralized. As the piston is pushed downwardly through chamber 18 bythe increasing volume of fluid F, the peripheral O-ring 64 of piston 60remains in sealing engagement with the interior side wall surface ofreceptacle 12 so that chamber regions 86 and 89 remain separated fromone another. No fluid enters region 89 below piston 60. When theselected amount of fluid has been added to the receptacle, hypodermicsyringe H is disengaged from assembly 10. For human blood work, theselected volume of blood may be, for example, 50 mi. This volume ispreferred because it typically yields approximately 5 mi ofplatelet-rich blood product. Other volumes may be used as required byparticular applications.

After the desired amount of blood product or other fluid biologicalproduct is introduced into the tubular receptacle, syringe H isdisengaged from port 44 and closure 48 is reengaged with the port.Tubular receptacle 12 is then placed in a conventional centrifuge,either by itself or with other fluid filled tubular assemblies inaccordance with this invention. Again, base 15 supports receptacle 12 ina stable, upright condition in the centrifuge machine. The loadedcentrifuge is operated in an established manner for a selected time(e.g. preferably 5-7 minutes) in order to separate the constituentcomponents of blood or other fluid sample F. Various known types ofcentrifuge machines may be employed for this task. A single round ormultiple rounds of centrifuging may be utilized so that the selectedbiological product F is separated into two or more constituentcomponents as are required for a particular application.

After centrifuging is complete, FIG. 5, assembly 10 is removed from thecentrifuge and supported by its annular base 15 on the table or othersupport surface. In cases where fluid sample F comprises a blood sample,the centrifuged sample may appear as shown therein. Specifically,centrifuging causes the red blood cells 79 to collect in a dark redlayer proximate the bottom of receptacle 12 and immediately adjacentpiston 60. A discrete layer of plasma 80 exhibiting a yellow color isformed in the upper region of chamber 18 above red blood cells 79. Inalternative centrifuging applications, an intermediate layer ofplatelets in the form of a white “buffy” coat may be disposed betweenthe plasma and red blood cells layers. In embodiments when other fluidbiological products are centrifuged, two or more discrete constituentcomponent layers are formed in an analogous manner within the receptaclechamber above the piston. In all cases, piston 60 remains in sealinginterengagement with the interior wall of receptacle 12 such that theseparated biological constituents are maintained securely within chamber18 above the piston. Indeed, during the centrifuging process, thediameter of the O-ring typically expands somewhat to provide an evenmore securing sealing interengagement with the interior cylindrical wallof the receptacle.

The user next aspirates one or more layers of the sequesteredconstituent components from the centrifuged fluid. This is accomplishedby engaging one or more aspirating syringes S with assembly 10 in themanner shown in FIG. 6. For the blood product example that has beendescribed herein, the user typically wishes to first aspirateplasma/platelets using a syringe S. Initially, the user removes closure48, FIG. 1 and engages the syringe with port 44. The syringe is operatedto aspirate the upper layer of plasma 80 from the chamber 18 throughconical channel 42 and port 44. Plasma is drawn through the commoninlet/outlet port and into a respective syringe. As fluid F is removedfrom the tubular receptacle, vent plug 28 allows air to be pulled ordrawn into lower region 89 of chamber 18 as indicated by arrow 88. Againpressure within receptacle 12 is neutralized, a vacuum within lowerchamber region 89 is avoided and piston 60 is driven upwardly asindicated by arrows 90 in FIG. 6. Concave surface 66 of piston 60enables the piston to better maintain a fluid-tight seal so thatintermixing and cross contamination of the separated constituents areminimized. Conical channel 42 facilitates and improves removal andcollection of the plasma/platelets 8 during aspiration.

After the plasma is completely removed, the user may replace the firstsyringe, which has been used to remove the plasma, with a second syringedesigned to aspirate red blood cells. Aspiration may continue using thenew syringe to remove red blood cells 79 through port 44. Piston 60continues to be driven upwardly within tubular chamber 18 whilemaintaining sealing interengagement with the interior side wall of thetubular receptacle. Three constituent layers (plasma, platelets and redblood cells) and other biological products may be analogously aspiratedin a sequential manner following centrifugation. Platelets, plasma, bonemarrow aspirate and other fluid constituent can thereby be effectivelysequestered, retrieved and utilized as needed for surgical/wound careprocedures. After aspiration is completed, the remaining (unaspirated)red blood cells within the assembly and assembly 10 itself may bedisposed of in a medically acceptable manner.

During the foregoing process, filter 32 in the vent plug effectivelyrestricts particles and bioburdens from entering chamber 18 through thevent. This reduces the risk of contamination of the fluid duringinjection and aspiration.

Although the foregoing example depicts the use of centrifuge tubeassembly in connection with the separation and aspiration of constituentblood components, it should be understood that the tube may be usedequally effectively to separate and aspirate a wide variety ofalternative biological products. These include stem cells, bone marrowaspirate and various other fluids/chemicals.

The centrifuge tube disposed here may be employed in a wide variety ofmedical, biomedical, veterinary and other types of procedures. Whenveterinary blood work is involved, the tube will typically comprise amuch larger volume that is utilized during human blood work.

The devices and processes described above are particularly effective inallowing a blood sample to be conveniently separated into discrete bloodproducts, which may then be sequentially aspirated or removed so that aplatelet-rich product is conveniently obtained. This entire procedure isperformed without excessive mixing or cross-contamination of theindividual components. The separation process is performed more quickly,inexpensively, efficiently and effectively then has hereto been possibleusing known centrifuge tubes. The present device is especiallyadvantageous due to its use of relatively few working parts.Manufacturing the assembly is thereby facilitated and its attendant costis reduced considerably. By the same token, the centrifuge andaspiration process is performed much more quickly and easily then isaccomplished using conventional products, including the apparatus ofU.S. Pat. No. 7,179,391 for example.

The centrifuge tube assembly of the present invention improves themanufacture of centrifuge tubes used for the purposes described herein.In particular, the present invention totally eliminates the need to useaspirating pipes within the centrifuge tube. This greatly simplifies andreduces the expense of manufacturing such products. Moreover, bothaspiration and injection may be performed more quickly and reliablywithout aspiration pipes. To eliminate these components, it is acritical that a pressure neutralizing vent and inlet/outlet port mustcommunicate with respective regions of the centrifuge tube chamberseparated by (i.e. located on opposite sides of) the sealing piston ordiaphragm. In this way, fluids may be injected into and aspirated fromthe tube chamber directly through a common inlet/outlet port and withoutthe need for a separate aspirating pipe attached to the inlet/outletport and extending through the piston or diaphragm. The presentinvention also eliminates problems that can often occur from the use ofaspirating pipes, namely kinking or the pipe and resulting malfunctionof the tube.

It should be understood that other variations and modification of thecentrifuge tube assembly may be employed within the scope of thisinvention. The terms “upper end” and “lower end” may be usedinterchangeably and should be construed broadly to refer to therespective ends or locations proximate the respective ends of the tubeas indicated, for example, in the alternative orientations shown inFIGS. 5 and 7 respectively.

In the alternative version shown in FIG. 7, tube 10 may be employed toaspirate red blood cells first. In particular, the blood product isinitially added as previously shown in FIG. 4. Assembly 10 is theninverted as shown in FIG. 7 so that the vent plug 28 is positioned atthe top end and the inlet/outlet port 44 is positioned at the lower endof the tube. In this orientation, tube 10 is placed into the centrifugemachine. As previously indicated, the attached cover 50 includes a flattop surface that allows the inverted assembly to sit stably within thecentrifuge machine. Centrifuging is then performed in accordance withthe selected manner so that the constituent components of the fluidproduct, namely red blood cells 79 and plasma 80 are again separated asshown in FIG. 7. In this example, the red blood cells constitute thelower layer of the centrifuge fluid, and because the assembly has beeninverted, the red blood cells 79 are adjacent to the inlet/outlet port44. After centrifuging is completed, cap 50 is removed, closure 48 isdisengaged from port 44 and a hypodermic needle is engaged with theinlet/outlet port so that red blood cells may be aspirated first fromthe centrifuge tube assembly. As in the previously described embodiment,vent plug 28 neutralizes or equalizes the air pressure within thereceptacle so that the piston 60 is drawn upwardly during aspiration tofacilitate removal initially of the red blood cells 79, and subsequentlythe plasma 80 from the receptacle.

It should be further understood that the centrifuge tube assemblies ofthis invention may be employed to separate various other types ofbiological products, fluids and chemicals. Likewise, in suchapplications the individual components may be sequestered and removedquickly and conveniently without undue mixing and cross-contamination.

In still other versions of this invention, the inlet/outlet port andvent may be installed in alternative locations of the receptacle incommunication with the upper and lower chamber regions respectively.These may include alternative locations in the side wall or elsewhere.In all versions, the piston must separate and isolate the upper andlower chamber regions from one another so that the inlet/outlet port andthe vent communicate with different respective chamber regions, fluid issequestered in the upper chamber region and the assembly therebyoperates effectively without the need for aspirating pipes.

From the foregoing it may be seen that the apparatus of this inventionprovides for a centrifuge tube, which enables biological products suchas blood, stem cells, bone marrow aspirate and the like to beeffectively separated into constituent components and aspirated afterthe biological product has been centrifuged. While this detaileddescription has set forth particularly preferred embodiments of theapparatus of this invention, numerous modifications and variations ofthe structure of this invention, all within the scope of the invention,will readily occur to those skilled in the art. Accordingly, it isunderstood that this description is illustrative only of the principlesof the invention and is not limitative thereof.

Although specific features of the invention are shown in some of thedrawings and not others, this is for convenience only, as each featuremay be combined with any and all of the other features in accordancewith this invention.

Other embodiments will occur to those skilled in the art and are withinthe following claims:

What is claimed is:
 1. A centrifuge tube assembly for separating andaspirating constituent components of a fluid biological product, saidassembly comprising: a receptacle having an interior chamber forreceiving the fluid biological product therein; a piston mounted withinsaid chamber and being slidable through said chamber while maintainingsealing engagement with an interior surface of a side wall of saidreceptacle; a common inlet and outlet port supported by said receptacleand communicating with a first region of said chamber on one side ofsaid piston; a vent supported by said receptacle and communicating witha said second region of said chamber on an opposite side of said piston;and hypodermic injecting and aspirating syringes, which are selectivelyinterengaged with said common inlet and outlet port outside of saidreceptacle; the fluid biological product being injected by saidinjecting syringe through said common port into said first region ofsaid chamber and said receptacle being centrifuged to separate the fluidproduct into the constituent components thereof, which components aredisposed in respective fluid layers in said chamber, whereby one or moreof the fluid layers may be aspirated through said common inlet andoutlet port by said aspirating syringe, said vent neutralizing pressurewithin said second region of said receptacle chamber as fluid isinjected into said chamber and as constituent components are aspiratedfrom said chamber through said common inlet and outlet port.
 2. Theassembly of claim 1 in which said receptacle includes an elongate tubeand said piston includes a cylindrical element having a generallycircular peripheral shape conforming to said interior surface of saidside wall of said receptacle, said piston being driven toward a lowerend of said tube exclusively in response to hydraulic pressure exertedby fluid biological product injected into said chamber and toward anupper end of said tube exclusively in response to suction created insaid chamber by aspiration of the constituent components from saidchamber.
 3. The assembly of claim 1 in which said receptacle supports acap through which said common inlet and outlet is formed.
 4. Theassembly of claim 1 in which a lower end of said receptacle carries anannular base for supporting said receptacle to extend upwardly from anunderlying supportive surface, said vent being formed through said lowerend of said receptacle interiorly of said annular base.
 5. The assemblyof claim 1 further including a closure that is removably attached tosaid common inlet and outlet port outside of said chamber forselectively opening said port to permit introduction of the fluidbiological product into said chamber and aspiration of a separatedconstituent component therefrom and closing said port while saidreceptacle is being centrifuged.
 6. The assembly of claim 1 in whichsaid piston carries an O-ring that sealingly interengages said interiorsurface of said side wall.
 7. The assembly of claim 1 in which saidpiston includes a concave face directed toward said region of saidchamber between said piston and said cap.
 8. The assembly of claim 3 inwhich said cap includes a tapered channel that communicates with saidcommon inlet and outlet port for facilitating aspiration of the one ormore fluid layers.
 9. The assembly of claim 1 in which said ventincludes a vent plug received in a vent hole formed through saidreceptacle, said vent plug carrying a filter for restricting the entryof contaminants into said second region of said chamber through saidvent.
 10. The assembly of claim 1 further including a cover that isremovably interengageable with said receptacle for selectively enclosingan exterior section of said common inlet and outlet port.
 11. Theassembly of claim 10 in which said cover includes a flat top surface forslidably supporting said receptacle in an inverted condition forcentrifuging.
 12. The assembly of claim 1 in which said common inlet andoutlet port includes a female port for selectively and receivablyinterengaging said injecting and aspirating syringes.
 13. A centrifugetube assembly for use selectively and operatively with a hypodermicinjecting syringe and a hypodermic aspirating syringe to separate andaspirate constituent components of a fluid biological product, saidcentrifuge tube assembly comprising: a receptacle having an interiorchamber for receiving a fluid biological product therein; a pistonmounted within said chamber and being slidable through said chamberwhile maintaining sealing engagement with an interior surface of a sidewall of said receptacle; a female common inlet and outlet port supportedby said receptacle in communication with a first region of said chamberlocated on one side of said piston, said female common inlet and outletport configured for selectively receiving the injecting syringe and theaspirating syringe; and a vent supported by said receptacle incommunication with a second region of said chamber located on anopposite, second side of said piston; fluid biological product beinginjected through said female common inlet and outlet port into saidfirst chamber region and said receptacle being centrifuged to separatethe fluid product into constituent components thereof, which componentsare disposed in respective layers in said first chamber region; wherebyone or more of the fluid layers may be aspirated through said femalecommon inlet and outlet port, said vent neutralizing air pressure withinsaid second chamber region as fluid is injected into and as constituentcomponents are aspirated from said first chamber region.
 14. Theassembly of claim 13 in which said receptacle supports a cap throughwhich said common inlet and outlet is formed.
 15. The assembly of claim13 in which said cylindrical element carries an O-ring for sealably andslidably interengaging an interior surface of said side wall of saidreceptacle.
 16. The assembly of claim 13 in which said common inlet andoutlet port includes a female Luer™ port.
 17. A method of separatingfluid biological product into constituent components using a centrifugetube assembly, which assembly includes an elongate tubular receptaclehaving an interior chamber, a piston mounted for sliding within thereceptacle chamber while maintaining sealing engagement with an interiorsurface of a side wall thereof, a common inlet and outlet port supportedby the receptacle and configured for injecting fluid biological productinto and aspirating constituent components from a first region of thereceptacle on one side of the piston and, a vent supported by thereceptacle and communicating with a second region of the chamber on anopposite side of the piston, said method comprising: injecting the fluidbiological product into the receptacle through the common inlet andoutlet port into the first region of the chamber such that the hydraulicpressure of the injected fluid drives said piston through the receptacleand until said receptacle is filled to a selected level by thebiological product; closing the common inlet and outlet port;centrifuging the receptacle to separate the fluid biological productinto constituent components; opening the common inlet and outlet port;and aspirating one or more of the constituent components from the firstchamber through the common inlet and outlet port such that a suction isgenerated to draw said sealing piston through the receptacle in thedirection of the common inlet and outlet port, wherein the ventneutralizes pressure within the second chamber region as fluid isintroduced into and constituent components are aspirated from said firstchamber region.
 18. The method of claim 17 in which the common inlet andoutlet port includes a Luer™ port through which biological product isinjected and constituent components are aspirated.
 19. The method ofclaim 18 in which the common inlet and outlet port includes a femaleLuer™ port.